The prior art is already aware of various arrangements of hydraulically-controlled pivotal buckets supported on a tractor or the like. These prior art arrangements commonly have hydraulic pumps and valves and cylinder assemblies, all for pivotally controlling and positioning the bucket, for the purpose of digging and loading and dumping the bucket. One example of such prior art is seen in U.S. Pat. No. 3,084,817 where an oscillatory digger is disclosed, and the present invention also relates to an oscillatory type of arrangement for the material handling bucket.
Accordingly, it is an object of this invention to provide an oscillatory electro-hydraulic system for a material handling bucket wherein the bucket can be completely and accurately controlled by means of the hydraulic power applied through cylinder assemblies connected with the bucket. Further, the present invention incorporates an electric system wherein the two cylinder assemblies employed in pivoting the bucket are pressurized according to the extension and contraction of the assemblies which control the electric system in the extending and contracting action itself. In this arrangement, the present invention employs two cylinder assemblies which are pressurized by means of a hydraulic pump and which have a valve interposed between the assemblies for selective directing of fluid pressure between the two cylinder assemblies, and the arrangement is such that only one of the two assemblies can be actuated for pivoting the bucket, while the other of the two assemblies can simply be free to extend or contract in response to the pressurizing and actuation of the first cylinder assembly.
That is, the present invention provides an oscillatory electro-hydraulic system wherein two cylinder assemblies are available but only one of the two can be utilized, in one mode of operation, and the two assemblies can be operative, in another mode of operation, when it is desired that the oscillatory action be effected in the control of the material handling bucket. In accomplishing this, the electric system is incorporated in the overall arrangement and is responsive to the extension and contraction of the cylinder assemblies, and the electric system is electrically connected with a hydraulic valve to thereby control the flow to one of the two cylinder assemblies, when it is desired that the additional one of the two assemblies be pressurized for pivoting of the bucket. Further, it will be seen and understood that the entire arrangement of the electro-hydraulic system disclosed herein can be applied to the conventional loader bucket, back-hoe, and like arrangements where the member holding the material is pivotally mounted and under the influence of hydraulic cylinders, as employed herein.
Another object of this invention is to provide an oscillatory electro-hydraulic system which incorporates the aforementioned alternative actions of pressurizing only one of two cylinder assemblies or of pressurizing both of the cylinder assemblies, with the latter action being utilized in the oscillatory mode of operation of the entire system. Further, in accomplishing this particular objective, the oscillatory mode is automatically repeated, and it is shown herein to be controlled by an electric system wherein the operator need only push an electric stop button in order to deactivate the oscillatory mode of this invention. Still further, the energizing or de-energizing of the oscillatory mode can be accomplished at any point in the cycle of the operation of the cylinder assemblies.
Other objects and advantages will become apparent upon reading the following description in light of the accompanying drawings.